Cast iron is different from pig iron and is made by melting pig iron with scrap iron and coke using hot air blast. The blast air causes the iron oxides, flux, and coke to react and iron, carbon monoxide and blastfurnace slag is produced. Cast iron is taken in pudding furnace and melted by hot blast of air. As the mixture of iron ore, coke and limestone heats, the hot waste gases are collected and cleansed. The first metallurgical step is to reduce iron ore to metallic iron, a process which is mostly carried out in a blast furnace, using coke as both a fuel and reducing agent. The iron found in iron ores are found in the form of iron oxides. The calcined ore is mixed with lime stone caco 3 flux and ore in the ratio of 8. The charge is placed a giant chimney called a blast. Blast furnace, a vertical shaft furnace that produces liquid metals by the reaction of a flow of air introduced under pressure into the bottom of the furnace with a mixture of metallic ore, coke, and flux fed into the top. The process of the extraction of iron is carried out by the following steps. The extraction of iron from its ores is quite a technical process. The iron is reduced from the ore by carbon in the coke, the limestone aiding slag separation from the molten iron. Extraction of iron using blast furnace definition, examples. Coke is produced by heating coal in the absence of air.
The oxygen must be removed from the iron iii oxide in. These materials are loaded into the blast furnace from the top while a blast of hot air is introduced into it from beneath via small pipes known as tuyeres. The main compounds of dust are iron oxides with a share of heavy nonferrous metal oxides, mainly zinc. Why does iron have to be extracted in a blast furnace iron can be extracted by the blast furnace because it can be displaced by carbon. Oct 04, 2016 blast furnace extraction of iron from blast furnace class 12 ncert chemistry blast furnace working animation extraction of iron metallurgy of iron. The iron ore is first roasted in air to produce iron iii oxide which is mixed with coke and limestone and then further heated to a very high temperature in a blast furnace. Iron ores such as haematite contain iron iii oxide, fe 2 o 3. Blast furnaces produce pig iron from iron ore by the reducing action of carbon supplied as coke at a high temperature in the presence of a fluxing agent such as limestone. A mixture of crushed iron ore, coke an almost pure form of carbon and limestone is fed into the top of the blast furnace. Processes and procedures in the extraction of iron gulpmatrix. Blast furnaces are used to produce pig iron from iron ore for subsequent. The molten iron and blastfurnace slag is collected at the base of the furnace, while the gases are recirculated for fuel in the sinter process, after. In a blast furnace, fuel coke, ores, and flux limestone are continuously supplied through.
The most common ore of iron is called haematite iron iii oxide. During the production of pig iron in a blast furnace a large quantity of dust is generated. The blast furnace is cylindrical steel vessel limed 6m in diameter. Blast furnace slag an overview sciencedirect topics. The iron obtained from blast furnace contains about 4% carbon and some other impurities. Extracting iron from iron ore using a blast furnace introduction the common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Aug 03, 2011 extracting iron from iron ore using a blast furnace introduction the common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Cbse ncert notes class 12 chemistry isolation of elements. The production of iron from its ore involves an oxidationreduction reaction carried out in a blast furnace. Direct biohydrometallurgical extraction of iron from ore osti. Analysis of slag flow in blast furnace during the extraction. Iron ores are reduced by coke carbon in a blast furnace. Total energy consumption by iron production using conventional methods is. Iron ores such as haematite contain ironiii oxide, fe 2o 3.
Extraction of iron on a match head resource rsc education. The principle of blast furnace operational technology and. The diagram shows the blast furnace for the extraction of iron from its ore, taken as haematite. Coke is cheap and provides both the reducing agent for the reaction and also the heat source. The ore is loaded into a blast furnace along with measured quantities of coke and limestone. Pelletizing a pellet plant contains a series of balling drums where the iron ore concentrate is formed into soft pellets, in much the same manner that one rolls a snowball, to make a pellet about the size of a marble between 14 and 12. Usage of the blast and cupola furnace remained widespread during the song and tang dynasties.
Iron from the blast furnace is an alloy of about 96 per cent iron with carbon and some other impurities. Blast furnaces are used continuously and are only shut down when their brick lining needs replacing. It is dropped into the top of a blast furnace along with coke purified coal, almost pure carbon and limestone calcium carbonate. A blast furnace is a gigantic, steel stack lined with. Iron ore is usually a mixture of iron and vast quantities of impurities such as sand and clay referred to as gangue. Processes and procedures in the extraction of iron. The molten iron and blast furnace slag is collected at the base of the furnace, while the gases are recirculated for fuel in the sinter process, after separation of particulate material cooper, 2005. Iron ore, as mined, is a combination of iron with oxygen and various other unwanted substances, generally known as gangue. It constitutes 5 percent by weight of the earths crust, and it is the. Jul 21, 2014 iron ores are reduced by coke carbon in a blast furnace. It is dropped into the top of a blastfurnace along with coke purified coal, almost pure carbon and limestone calcium carbonate. The purpose of a blast furnace is to chemically reduce and physically convert iron oxides into liquid iron called hot metal. Oxides ores of iron after concentration through calcinationroasting are mixed with limestone and coke and fed into a blast furnace from its top.
Iron does not exist on the earth as an element, but rather in the form of its oxides and sulphides in iron ore. Extraction of iron metallurgy blast furnace and reactions. A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. Hot combustion air is supplied to the furnace and some form of fuel used to raise the temperature.
Concentration of ore calcination or roasting of ore. On passing pre heated compressed air inside the furnace, four distinct zones are formed. The purpose of a blast furnace is to reduce the concentrated ore chemically to its liquid metal state. Mar 20, 2017 shows how iron ore, limestone, and coke are handled and prepared for the blast furnace in the making of iron. Extraction of iron very unreactive metals are found directly in the ground as elements, eg. Creating steel from lowgrade iron ore requires a long process of mining, crushing, separating, concentrating, mixing, pelletizing, and shipping. Blast refers to the combustion air being forced or supplied above atmospheric pressure in a blast furnace, fuel, ores, and flux are continuously supplied through the top of the furnace, while a hot blast of air sometimes with. A dryprocess dust collector for blast furnace is equipment for cleansing blast furnace gas. Smelting method used in the extraction of iron definition. After iron ore is mined it is send to the blast furnace. The blast air causes the iron oxides, flux, and coke to react and iron, carbon monoxide and blast furnace slag is produced. Extracting iron iron and aluminium gcse chemistry single.
Three substances are needed to enable to extraction of iron from its ore. The blast furnace operates at 1900 c in order to smelt iron from iron ore. The common ores of iron are both iron oxides, and these can be reduced to iron by heating them with carbon in the form of coke. Ironmaking blast furnaces consist of several zones. The extraction of iron from its ore is a long and subdued process, that helps in separating the useful components from the waste materials such as slag. How a blast furnace works introduction the purpose of a blast furnace is to chemically reduce and physically convert iron oxides into liquid iron called hot metal. In the basic oxygen process bop, molten iron from a blast furnace and iron scrap are refined in a furnace by lancing or injecting highpurity oxygen. The flowcharacteristic of blast furnace slags is strongly influenced by the extent of reduction of iron oxide at low temperature in the granular zone besides being influenced by the composition, and the quality and the quantity of the gangue in the iron bearing materials. Metal is cast into ingots or in the ladle for further refining like steel making. Extracting iron from iron ore using a blast furnace. Hot air is blasted in from the side to provide oxygen that allows some of the carbon to burn, releasing enough heat to raise the temperature above 1500 o c. The most common ore of iron is called haematite ironiii oxide. This page looks at the use of the blast furnace in the extraction of iron from iron ore, and the conversion of the raw iron from the furnace into various kinds of steel. Write the equations for each of the following reactions.
Milestones of our blast furnace operation technologies tamura categorized our history of pig iron making into the following three periods, in an article. The oxygen must be removed from the ironiii oxide in. The blast furnace after iron ore is mined it is send to the blast furnace iron is extracted from its ore in a blast furnace. The slag and molten iron are tapped off from the bottom of the furnace, the slag being. The blast furnace is a cylindrical tower like structure about 25m to 35m high. Mar 31, 2014 why does iron have to be extracted in a blast furnace iron can be extracted by the blast furnace because it can be displaced by carbon.
Extraction of iron in a blast furnace reduction haematite o. This is more efficient method than electrolysis because it is more cost effective 4. In a blast furnace oxide ores of iron, after concentration through calcinationroasting are mixed with limestone. Pdf leaching of zinc and iron from blast furnace dust in. The slag is in molten state and separates out from iron. This takes place in a blast furnace named after blasts of air 20% oxygen, heated to c, which are blasted into the bottom of the furnace. Processing them in a blast furnace or in wellknown alternatives corex, midrex, hyll, finemet, itmk3, etc. Extraction of iron in a blast furnace the significant reactions occuring within the blast furnace can be described via the following steps showing how the reducing agent varies depending on the height in the furnace i.
Blast refers to the combustion air being forced or supplied above atmospheric pressure. Iron processing, use of a smelting process to turn the ore into a form from which products can be fashioned. The blast furnace is a huge, steel stack lined with refractory brick, where iron ore, coke and limestone are dumped into the top, and preheated air is blown into the bottom. Milestones of our blast furnace operation technologies tamura categorized our history of pigiron making into the following three periods, in an article. Extraction of iron by the blast furnace process extraction. They are then used to help heat the air blast, required if blast furnace is to reach the high temperatures needed to produce molten iron. Iron ore, haematite often contains sand with iron oxide, fe 2 o 3. In addition, blast furnace operation requires 23,360 mjmetric ton of hot metal. The iron ore concentrate is now mixed and ready for the pelletizing process. Extraction of iron study material for iit jee askiitians. Extraction of iron examples, answers, activities, experiment. Hottest part of the furnace at the bottom of the furnace, adjacent to the hot air blast entry points, the temperature reaches around 1800.
Blast furnace slag bfs which is defined as the nonmetallic product consisting essentially of silicates and alumina silicates of calcium and other bases, that is developed in a molten condition simultaneously with iron in a blast furnace by astm c 12516 2016 has been widely used in construction industry for more than 80 years. Iron fe is a relatively dense metal with a silvery white appearance and distinctive magnetic properties. So, most iron from the blast furnace is converted into steel by removing some of the carbon. The top of the furnace is closed by a cupcone feeder. Blast furnace it is a tall cylindrical furnace made of steel.
The earliest evidence of the use of a blast furnace in china dates to the 1st century ad, and cupola furnaces were used as early as the warring states period 403221 bc. Included in this article also is a discussion of the mining of iron and of its preparation for smelting. Iron ores such as haematite contain ironiii oxide, fe 2 o 3. The energy in blast furnace gas in the forms of pressure and temperature is recovered by a trt generator after passing through the dust collector. The common ores of iron are both iron oxides, and these can be reduced to iron by heating. The energy in the furnace gas has been lost in the conventional wetprocess dust collector as the. Smelting the concentrated ore is mixed with calculated quantity of coke, limestone and the mixture is put in the blast furnace from top. Shows how iron ore, limestone, and coke are handled and prepared for the blast furnace in the making of iron. Iron smelting may have been introduced into china through central asia. Iron is extracted from its ore, haematite, by reduction with carbon.
Extraction of iron from haematite grade 12 science notes. The iron ore is first roasted in air to produce ironiii oxide which is mixed with coke and limestone and then further heated to a very high temperature in a blast furnace. They are the starting materials for the technical extraction of pig iron in the blast furnace. Extracting iron redox, extraction of iron and transition. Extraction of iron in a blast furnace iron is also below carbon in the reactivity series, so therefore carbon can be used to reduce it note. After the extraction process, some coke oven gas is returned to the battery where it is mixed with blast furnace gas for use in heating the coking chambers and the. He washed ore is then strongly heated in the absence of air to expel water shacking to it.
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